We have made use of high resolution, proton Magnetic Resonance Spectroscopy in our study of HIV-infected patients. Since neuronal damage occurs in the intermediate or late stages of the disease, our objective was to determine whether MRS could detect metabolic alterations in the early stages. We also examined patients in the intermediate stages of AIDS Dementia Complex (ADC 1). In order to obtain "pure" spectra of cortical gray matter and selected white matter regions, we employed a one-dimensional method of MRS imaging using chemical shift. This past year we have examined 29 symptomatic and asymptomatic patients as well as six healthy controls. MRS data showed two distinct differences between the patients and normal controls. The group of patients with ADC showed a significantly lower ratio of NAA to Cr in gray matter than those of both the control group and the group of patients without ADC. This last group was characterized by a higher ratio of mI to Cr in white mat ter and a similar NAA/Cr in both gray and white matter as compared to the control group. These results suggest that high resolution MRS will indeed aid in the evaluation of frontal lobe metabolism by identifying changes in brain metabolism. As part of the AIDS Clinical Trials Group, we are also using this method to evaluate patients enrolled in the study involving the ACTG-301, memantine NMDA receptor antagonist.